My dear departed mother worked in the restaurant biz her whole life, she was the sweetest nicest hostess you'd ever want to meet, (truly). She made a very good living on tips as she worked in a high end dinner house with lots of big tippers. She also served the cocktails which always had the best tippers of all. The reputation for black folks being the worst tippers, and even non-tippers was true according to her experience, and not just a trope as many of the defenders of minorities will claim.
I can second that from personal experience. Even my fellow waiters who were themselves black, wanted nothing to do with them.